Are you changing your oil too many times ?

I run synthetic oil and a good filter. On the wife's old Ford, it was changed twice a year with a oil filter at every change and mid way through to the next change. The car seen approx. 15 - 18 miles per year.
The car totaled 175,000 miles before the original trans gave up a bit. No burning of the oil.
Did this for 142,000 miles over 9 years of ownership.

Same for my 2003 V6 Dakota. 215,000+ miles. Burns about a quart in 6 months.
Ownership of this ride is since 10/09.
Same for the wife's truck, 1998 Durango, 285,000+ miles, burns slightly more in 6 months.

As long as the engine doesn't leak or burn much more than a quart between oil filter changes, synthetic is used. If it burns more than that, Dino oil is used.